The terahertz (THz, 1012 cycles per second, 1012 Hz) region or gap, which lies in between the infrared and millimeter spectral regions typically from 100 GHz to 15 THz, poses one of the most demanding challenges for technology and fundamental science today. Indeed, it is one of the least explored, yet most technologically transformative spectral regions.
One key current challenge is the lack of efficient and compact THz emitters/detectors with a broadband and gapless spectrum that can be tailored for various pump photon energies. The lacking of the efficient light sources and detectors is what makes the THz physics one of the least-explored parts in the entire electromagnetic spectrum. This is despite the fact that the technological demand underlies the entire field of sensing and communications to (1) push the gigahertz switching speed limit of today's logic/memory/wireless communication devices into the THz, and (2) extend the conventional visible/infrared spectrum of today's security screening/drug detection/biometrics/DNA chip applications to the THz spectrum, which is generally more transparent and has more distinct spectral signatures suitable for non-invasive and label-free evaluation. One key challenge for most applications is to develop ultrafast few-cycle THz pulses with extraordinary stability and gapless spectrum covering the entire THz region.
The invention provides such a THz pulse generators/sensors. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.